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Hoffmann UA, Lichtenberg E, Rogh SN, Bilger R, Reimann V, Heyl F, Backofen R, Steglich C, Hess WR, Wilde A. The role of the 5' sensing function of ribonuclease E in cyanobacteria. RNA Biol 2024; 21:1-18. [PMID: 38469716 PMCID: PMC10939160 DOI: 10.1080/15476286.2024.2328438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2024] [Indexed: 03/13/2024] Open
Abstract
RNA degradation is critical for synchronising gene expression with changing conditions in prokaryotic and eukaryotic organisms. In bacteria, the preference of the central ribonucleases RNase E, RNase J and RNase Y for 5'-monophosphorylated RNAs is considered important for RNA degradation. For RNase E, the underlying mechanism is termed 5' sensing, contrasting to the alternative 'direct entry' mode, which is independent of monophosphorylated 5' ends. Cyanobacteria, such as Synechocystis sp. PCC 6803 (Synechocystis), encode RNase E and RNase J homologues. Here, we constructed a Synechocystis strain lacking the 5' sensing function of RNase E and mapped on a transcriptome-wide level 283 5'-sensing-dependent cleavage sites. These included so far unknown targets such as mRNAs encoding proteins related to energy metabolism and carbon fixation. The 5' sensing function of cyanobacterial RNase E is important for the maturation of rRNA and several tRNAs, including tRNAGluUUC. This tRNA activates glutamate for tetrapyrrole biosynthesis in plant chloroplasts and in most prokaryotes. Furthermore, we found that increased RNase activities lead to a higher copy number of the major Synechocystis plasmids pSYSA and pSYSM. These results provide a first step towards understanding the importance of the different target mechanisms of RNase E outside Escherichia coli.
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Affiliation(s)
- Ute A. Hoffmann
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Elisabeth Lichtenberg
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Said N. Rogh
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Raphael Bilger
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Viktoria Reimann
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Florian Heyl
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Claudia Steglich
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
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Kanwal S, De-Eknamkul W. A Non-functional γ-Aminobutyric Acid Shunt Pathway in Cyanobacterium Synechocystis sp. PCC 6803 Enhances δ-Aminolevulinic Acid Accumulation under Modified Nutrient Conditions. Int J Mol Sci 2023; 24:ijms24021213. [PMID: 36674729 PMCID: PMC9864891 DOI: 10.3390/ijms24021213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023] Open
Abstract
To redirect carbon flux from the γ-aminobutyric acid (GABA) shunt to the δ-aminolevulinic acid (ALA) biosynthetic pathway, we disrupted the GABA shunt route of the model cyanobacterium Synechocystis sp. PCC 6803 by inactivating Gdc, the gene-encoding glutamate decarboxylase. The generated ΔGdc strain exhibited lower intracellular GABA and higher ALA levels than the wild-type (WT) one. The ΔGdc strain’s ALA levels were ~2.8 times higher than those of the WT one when grown with levulinic acid (LA), a competitive inhibitor of porphobilinogen synthase. Abiotic stress conditions including salinity induced by 10 mM NaCl and cold at 4 °C increased the ALA levels in ΔGdc up to ~2.5 and 5 ng g−1 cell DW, respectively. The highest ALA production in the ΔGdc cyanobacteria grown in BG11 medium was triggered by glucose induction, followed by glutamate supplementation with 60 mM of LA, thereby resulting in ~360 ng g−1 cell DW of ALA, that is >300-fold higher ALA accumulation than that observed in ΔGdc cyanobacteria grown in normal medium. Increased levels of the gdhA (involved in the interconversion of α-ketoglutarate to glutamate) and the hemA (a major regulatory target of the ALA biosynthetic pathway) transcripts occurred in ΔGdc cyanobacteria grown under modified growth conditions. Our study provides critical insight into the facilitation of ALA production in cyanobacteria.
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Phycobilisome breakdown effector NblD is required to maintain the cellular amino acid composition during nitrogen starvation. J Bacteriol 2021; 204:JB0015821. [PMID: 34228497 PMCID: PMC8765419 DOI: 10.1128/jb.00158-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small proteins are critically involved in the acclimation response of photosynthetic cyanobacteria to nitrogen starvation. NblD is the 66-amino-acid effector of nitrogen-limitation-induced phycobilisome breakdown, which is believed to replenish the cellular amino acid pools. To address the physiological functions of NblD, the concentrations of amino acids, intermediates of the arginine catabolism pathway and several organic acids were measured during the response to nitrogen starvation in the cyanobacterium Synechocystis sp. PCC 6803 wild type and in an nblD deletion strain. A characteristic signature of metabolite pool composition was identified, which shows that NblD-mediated phycobilisome degradation is required to maintain the cellular amino acid and organic acid pools during nitrogen starvation. Specific deviations from the wild type suggest wider-reaching effects that also affect such processes as redox homeostasis via glutathione and tetrapyrrole biosynthesis, both of which are linked to the strongly decreased glutamate pool, and transcriptional reprogramming via an enhanced concentration of 2-oxoglutarate, the metabolite co-regulator of the NtcA transcription factor. The essential role played by NblD in metabolic homeostasis is consistent with the widespread occurrence of NblD throughout the cyanobacterial radiation and the previously observed strong positive selection for the nblD gene under fluctuating nitrogen supply. Importance Cyanobacteria play important roles in the global carbon and nitrogen cycles. In their natural environment, these organisms are exposed to fluctuating nutrient conditions. Nitrogen starvation induces a coordinated nitrogen-saving program that includes the breakdown of nitrogen-rich photosynthetic pigments, particularly phycobiliproteins. The small protein NblD was recently identified as an effector of phycobilisome breakdown in cyanobacteria. In this study, we demonstrate that the NblD-mediated degradation of phycobiliproteins is needed to sustain cellular pools of soluble amino acids and other crucial metabolites. The essential role played by NblD in metabolic homeostasis explains why genes encoding this small protein are conserved in almost all members of cyanobacterial radiation.
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Regulation and function of tetrapyrrole biosynthesis in plants and algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:968-85. [PMID: 25979235 DOI: 10.1016/j.bbabio.2015.05.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/21/2015] [Accepted: 05/07/2015] [Indexed: 12/20/2022]
Abstract
Tetrapyrroles are macrocyclic molecules with various structural variants and multiple functions in Prokaryotes and Eukaryotes. Present knowledge about the metabolism of tetrapyrroles reflects the complex evolution of the pathway in different kingdoms of organisms, the complexity of structural and enzymatic variations of enzymatic steps, as well as a wide range of regulatory mechanisms, which ensure adequate synthesis of tetrapyrrole end-products at any time of development and environmental condition. This review intends to highlight new findings of research on tetrapyrrole biosynthesis in plants and algae. In the course of the heme and chlorophyll synthesis in these photosynthetic organisms, glutamate, one of the central and abundant metabolites, is converted into highly photoreactive tetrapyrrole intermediates. Thereby, several mechanisms of posttranslational control are thought to be essential for a tight regulation of each enzymatic step. Finally, we wish to discuss the potential role of tetrapyrroles in retrograde signaling and point out perspectives of the formation of macromolecular protein complexes in tetrapyrrole biosynthesis as an efficient mechanism to ensure a fine-tuned metabolic flow in the pathway. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Sangwan I, O'brian MR. Evidence for an inter-organismic heme biosynthetic pathway in symbiotic soybean root nodules. Science 2010; 251:1220-2. [PMID: 17799282 DOI: 10.1126/science.251.4998.1220] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The successful symbiosis of soybean with Bradyrhizobium japonicum depends on their complex interactions, culminating in the development and maintenance of root nodules. A B. japonicum mutant defective in heme synthesis in culture was able to produce heme as a result of its symbiotic association with the soybean host. The bacterial mutant was incapable of synthesizing the committed heme precursor delta-aminolevulinic acid (ALA), but nodule plant cells formed ALA from glutamate. In addition, exogenous ALA was taken up by isolated nodule bacteria of the parent strain and of the mutant. It is proposed that bacterial heme found in nodules can be synthesized from plant ALA, hence segments of a single metabolic pathway are spatially separated into two organisms.
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Yilmaz M, Kang I, Beale SI. Heme oxygenase 2 of the cyanobacterium Synechocystis sp. PCC 6803 is induced under a microaerobic atmosphere and is required for microaerobic growth at high light intensity. PHOTOSYNTHESIS RESEARCH 2010; 103:47-59. [PMID: 19937118 DOI: 10.1007/s11120-009-9506-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 11/04/2009] [Indexed: 05/28/2023]
Abstract
Cyanobacteria, red algae, and cryptomonad algae utilize phycobilin chromophores that are attached to phycobiliproteins to harvest solar energy. Heme oxygenase (HO) in these organisms catalyzes the first step in phycobilin formation through the conversion of heme to biliverdin IXalpha, CO, and iron. The Synechocystis sp. PCC 6803 genome contains two open reading frames, ho1 (sll1184) and ho2 (sll1875), whose products have in vitro HO activity. We report that HO2, the protein encoded by ho2, was induced in the cells growing under a microaerobic atmosphere [0.2% (v/v) O(2)], whereas HO1 was constitutively expressed under both aerobic and microaerobic atmospheres. Light intensity did not have an effect on the expression of both the HOs. Cells, in which ho2 was disrupted, were unable to grow microaerobically at a light intensity of 40 micromol m(-2) s(-1), but did grow microaerobically at 10 micromol m(-2) s(-1) light intensity. These cells grew normally aerobically at both light intensities. Comparative analysis of complete cyanobacterial genomes revealed that possession of two HOs is common in cyanobacteria. In phylogenetic analysis of their amino acid sequences, cyanobacterial HO1 and HO2 homologs formed distinct clades. HO sequences of cyanobacteria that have only one isoform were most similar to HO1 sequences. We propose that HO2 might be the more ancient HO homolog that functioned under low O(2) tension, whereas the derived HO1 can better accommodate increased O(2) tension in the environment.
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Affiliation(s)
- Mete Yilmaz
- Division of Biology and Medicine, Brown University, Providence, RI 02912, USA
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Abstract
Protein dynamics are likely to play important, regulatory roles in many aspects of photosynthetic electron transfer, but a detailed description of these coupled protein conformational changes has been unavailable. In oxygenic photosynthesis, photosystem I catalyzes the light-driven oxidation of plastocyanin or cytochrome c and the reduction of ferredoxin. A chlorophyll (chl) a/a' heterodimer, P(700), is the secondary electron donor, and the two P(700) chl, are designated P(A) and P(B). We used specific chl isotopic labeling and reaction-induced Fourier-transform infrared spectroscopy to assign chl keto vibrational bands to P(A) and P(B). In the cyanobacterium, Synechocystis sp. PCC 6803, the chl keto carbon was labeled from (13)C-labeled glutamate, and the chl keto oxygen was labeled from (18)O(2). These isotope-based assignments provide new information concerning the structure of P(A)(+), which is found to give rise to two chl keto vibrational bands, with frequencies at 1653 and 1687 cm(-1). In contrast, P(A) gives rise to one chl keto band at 1638 cm(-1). The observation of two P(A)(+) keto frequencies is consistent with a protein relaxation-induced distribution in P(A)(+) hydrogen bonding. These results suggest a light-induced conformational change in photosystem I, which may regulate the oxidation of soluble electron donors and other electron-transfer reactions. This study provides unique information concerning the role of protein dynamics in oxygenic photosynthesis.
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Srivastava A, Beale SI. Glutamyl-tRNA reductase of Chlorobium vibrioforme is a dissociable homodimer that contains one tightly bound heme per subunit. J Bacteriol 2005; 187:4444-50. [PMID: 15968053 PMCID: PMC1151790 DOI: 10.1128/jb.187.13.4444-4450.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2004] [Accepted: 03/10/2005] [Indexed: 11/20/2022] Open
Abstract
delta-Aminolevulinic acid, the biosynthetic precursor of tetrapyrroles, is synthesized from glutamate via the tRNA-dependent five-carbon pathway in the green sulfur bacterium Chlorobium vibrioforme. The enzyme glutamyl-tRNA reductase (GTR), encoded by the hemA gene, catalyzes the first committed step in this pathway, which is the reduction of tRNA-bound glutamate to produce glutamate 1-semialdehyde. To characterize the GTR protein, the hemA gene from C. vibrioforme was cloned into expression plasmids that added an N-terminal His(6) tag to the expressed protein. The His-tagged GTR protein was purified using Ni affinity column chromatography. GTR was observable as a 49-kDa band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. The native molecular mass, as determined by gel filtration chromatography, appeared to be approximately 40 kDa, indicating that native GTR is a monomer. However, when the protein was mixed with 5% (vol/vol) glycerol, the product had an apparent molecular mass of 95 kDa, indicating that the protein is a dimer under these conditions. Purified His(6)-GTR was catalytically active in vitro when it was incubated with Escherichia coli glutamyl-tRNA(Glu) and purified recombinant Chlamydomonas reinhardtii glutamate-1-semialdehyde aminotransferase. The expressed GTR contained 1 mol of tightly bound heme per mol of pep tide subunit. The heme remained bound to the protein throughout purification and was not removed by anion- or cation-exchange column chromatography. However, the bound heme was released during SDS-PAGE if the protein was denatured in the presence of beta-mercaptoethanol. Added heme did not inhibit the activity of purified expressed GTR in vitro. However, when the GTR was expressed in the presence of 3-amino-2,3- dihydrobenzoic acid (gabaculine), an inhibitor of heme synthesis, the purified GTR had 60 to 70% less bound heme than control GTR, and it was inhibited by hemin in vitro.
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Affiliation(s)
- Alaka Srivastava
- Division of Biology and Medicine, Brown University, Providence, RI 02912, USA
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Srivastava A, Lake V, Nogaj LA, Mayer SM, Willows RD, Beale SI. The Chlamydomonas reinhardtii gtr gene encoding the tetrapyrrole biosynthetic enzyme glutamyl-trna reductase: structure of the gene and properties of the expressed enzyme. PLANT MOLECULAR BIOLOGY 2005; 58:643-58. [PMID: 16158240 DOI: 10.1007/s11103-005-6803-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Accepted: 04/29/2005] [Indexed: 05/04/2023]
Abstract
Plants, algae, cyanobacteria and many other bacteria synthesize the tetrapyrrole precursor, delta-aminolevulinic acid (ALA), from glutamate by means of a tRNAGlu-mediated pathway. The enzyme glutamyl-tRNA reductase (GTR) catalyzes the first committed step in this pathway, which is the reduction of tRNA-bound glutamate to produce glutamate 1-semialdehyde. Chlamydomonas reinhardtii mRNA encoding gtr was sequenced from a cDNA and genomic libraries. The 3179-bp gtr cDNA contains a 1566-bp open reading frame that encodes a 522-amino acid polypeptide. After removal of the predicted transit peptide, the mature 480-residue GTR has a calculated molecular weight of 52,502. The deduced C. reinhardtii mature GTR amino acid sequence has more than 55% identity to a GTR sequence of Arabidopsis thaliana, and significant similarity to GTR proteins of other plants and prokaryotes. Southern blot analysis of C. reinhardtii genomic DNA indicates that C. reinhardtii has only one gtr gene. Genomic DNA sequencing revealed the presence of a small intron near the putative transit peptide cleavage site. Expression constructs for the full-length initial gtr translation product, the mature protein after transit peptide removal, and the coding sequence of the second exon were cloned into expression vector that also introduced a C-terminal His6 tag. All of these constructs were expressed in E. coli, and both the mature protein and the exon 2 translation product complemented a hemA mutation. The expressed proteins were purified by Ni-affinity column chromatography to yield active GTR. Purified mature GTR was not inhibited by heme, but heme inhibition was restored upon addition of C. reinhardtii soluble proteins.
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Affiliation(s)
- Alaka Srivastava
- Division of Biology and Medicine, Brown University, 02912, Providence, Rhode Island 02912, USA
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Chen W, Wright L, Li S, Cosloy SD, Russell CS, Lee S. Expression of glutamyl-tRNA reductase in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1309:109-21. [PMID: 8950186 DOI: 10.1016/s0167-4781(96)00117-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The biosynthesis of the hemes, chlorophylls, corrins and other tetrapyrroles begins with the synthesis of 5-aminolevulinic acid (ALA). The pathway is highly conserved except for the synthesis of ALA which is derived from glycine and succinyl CoA (C4) in most eukaryotes and from glutamate (C5) in most bacteria and in green plants. In C5, glutamyl-tRNA synthetase (GTS) converts glutamate to glutamyl-tRNA (glu-tRNA), which is reduced by glutamyl-tRNA reductase (GTR) to glutamyl-1-semialdehyde (GSA), which is converted by aminotransferase (GSA-AT) to ALA. Since GTS is also involved in protein synthesis and GSA can be converted to ALA non-enzymatically, it is highly probable that control of ALA synthesis and thus of the whole pathway resides in the GTR step. In Escherichia coli, GTR is the gene product of hemA. BL21(DE3), a protease-deficient strain which contains the T7 RNA polymerase gene in front of a lac promoter, was transformed with a pET14b-based vector, pWC01, harboring hemA in front of a T7 promoter and ORF1 which is transcribed in the opposite direction. The transformed strain, WC1201, secreted ALA and porphyrins into the medium. Induction of expression of hemA by WC1201 was optimized for concentration of inducer (IPTG, 5 mM), temperature (37 degrees C), presence of betaine and sorbitol (no change) and time of induction (2h). GTR was observable as a 46 kDa band by Brilliant blue G staining of SDS-PAGE gels. Sonicates of the induction mixture exhibited strong ALA synthesis activity which was enhanced by tRNAglu. Most of the activity was in the supernatant of the sonicate indicating that GTR is a soluble enzyme. The induced strain had more GTS activity than the uninduced strain which had more GTS activity than its parent wild-type strain. Autoradiography on native gradient PAGE showed that GTR expressed in vivo by induction of WC1201 had a molecular weight of approx. 117 kDa. Gel filtration of the induced sonicate showed a peak of enzymatic activity at about 126 kDa. When pET14b- or pUC19-based plasmids harboring hemA and ORF1, or importantly, a pUC19-based plasmid harboring only hemA and not ORF1, were expressed in an in vitro transcription-translation system, native gradient PAGE showed a product with a molecular weight of approximately 175 kDA. This expression was higher in the presence of tRNAglu. When the 117 kDa and 175 kDa proteins were excised from their native gels respectively, and run on SDS PAGE, autoradiography showed bands at 46 kDa. We conclude that GTR is present in both high molecular weight species. Since overexpression of hemA from pET14b-based plasmids is associated with increased glutamyl-tRNA synthetase activity, the 175 kDa species may represent different complexes of GTR, GTS and glutamyl-tRNA as observed in Chlamydomonas and the 117-126 kDa species may be an dimer of GTR associated with glu-tRNA or a complex of GTR, GTS and glu-tRNA. These possibilities are being investigated.
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Affiliation(s)
- W Chen
- Department of Biology, City College of New York, City University of New York, NY 10031, USA
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Tandeau de Marsac N, Houmard J. Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb05866.x] [Citation(s) in RCA: 270] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Rieble S, Beale SI. Structure and expression of a cyanobacterial ilvC gene encoding acetohydroxyacid isomeroreductase. J Bacteriol 1992; 174:7910-8. [PMID: 1459938 PMCID: PMC207525 DOI: 10.1128/jb.174.24.7910-7918.1992] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Acetohydroxyacid isomeroreductase (AHAIR) is the shared second enzyme in the biosynthetic pathways leading to isoleucine and valine. AHAIR is encoded by the ilvC gene in bacteria. A 1,544-bp fragment of genomic DNA containing the ilvC gene was cloned from the cyanobacterium Synechocystis sp. strain PCC 6803, and the complete nucleotide sequence was determined. The identity of the gene was established by comparison of the nucleotide and derived peptide sequences with those of other ilvC genes. The highest degree of sequence similarity was found with the ilvC gene from Rhizobium meliloti. The isolated Synechocystis ilvC gene complemented an Escherichia coli ilvC mutant lacking AHAIR activity. The expressed Synechocystis gene encodes a protein that has a molecular mass of 35.7 kDa and that has AHAIR activity in an in vitro assay. Polyclonal antibodies raised against purified Synechocystis AHAIR produced a single band on a Western blot (immunoblot) of a Synechocystis cell extract and detected the protein in an extract of an E. coli ilvC mutant strain that was transformed with a plasmid containing the Synechocystis ilvC gene. The antibody did not react with an extract of an E. coli ilvC mutant strain that was transformed with a control plasmid lacking the Synechocystis ilvC gene or with an extract of an E. coli IlvC+ control strain.
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Affiliation(s)
- S Rieble
- Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912
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Javor GT, Febre EF. Enzymatic basis of thiol-stimulated secretion of porphyrins by Escherichia coli. J Bacteriol 1992; 174:1072-5. [PMID: 1732201 PMCID: PMC206203 DOI: 10.1128/jb.174.3.1072-1075.1992] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1-Thioglycerol (TG) stimulates the synthesis of porphyrin in aerobically growing Escherichia coli. Here the levels of delta-aminolevulinate biosynthetic enzymes in untreated and TG-treated E. coli THU and PUC2 (a mutant of THU which overproduces porphyrins in the presence of thiols) cells were determined. TG treatment elevated the activity of glutamyl-tRNA reductase in both strains. The increased activity was not caused by activation of preexisting enzymes by thiols or by oxidizing agents but was dependent on new protein synthesis.
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Affiliation(s)
- G T Javor
- Department of Biochemistry and Microbiology, Loma Linda University School of Medicine, California 92350
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15
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Rieble S, Beale SI. Separation and partial characterization of enzymes catalyzing delta-aminolevulinic acid formation in Synechocystis sp. PCC 6803. Arch Biochem Biophys 1991; 289:289-97. [PMID: 1910318 DOI: 10.1016/0003-9861(91)90474-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Formation of the universal tetrapyrrole precursor, delta-aminolevulinic acid (ALA), from glutamate via the five-carbon pathway requires three enzymes: glutamyl-tRNA synthetase, glutamyl-tRNA reductase, and glutamate-1-semialdehyde (GSA) aminotransferase. All three enzymes were separated from extracts of the unicellular cyanobacterium Synechocystis sp. PCC 6803, and two of them, glutamyl-tRNA synthetase and GSA aminotransferase, were partially characterized. After an initial high speed centrifugation and differentiatial ammonium sulfate fractionation of cell extract, the enzymes were separated by successive affinity chromatography on Reactive Blue 2-Sepharose and 2',5'-ADP-agarose. All three enzyme fractions were required to reconstitute ALA formation from glutamate. The apparent native molecular masses of glutamyl-tRNA synthetase and GSA aminotransferase were determined by gel filtration chromatography to be 63 and 98 kDa, respectively. Neither glutamyl-tRNA synthetase nor GSA aminotransferase activity was affected by hemin concentrations up to 10 and 30 microM, respectively, and neither activity was affected by protochlorophyllide concentrations up to 2 microM. GSA aminotransferase was inhibited 50% by 0.5 microM gabaculine. The gabaculine inhibition was reversible for up to 1 h after its addition, if the gabaculine was removed by gel filtration before the enzyme was incubated with substrate. However, irreversible inactivation was obtained by preincubating the enzyme at 30 degrees C either for several hours with gabaculine alone or for a few minutes with both gabaculine and GSA. Neither pyridoxal phosphate nor pyridoxamine phosphate significantly affected the activity of GSA aminotransferase at physiologically relevant concentrations, and neither of these compounds reactivated the gabaculine-inactivated enzyme. It was noted that the presence of pyridoxamine phosphate in the ALA assay mixture produced a false positive color reaction even in the absence of enzyme.
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Affiliation(s)
- S Rieble
- Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912
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McKinney CE, Ades IZ. Production of delta-aminolevulinic acid: characterization of murine liver 4,5-dioxovaleric acid: L-alanine aminotransferase. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1991; 23:803-10. [PMID: 1773884 DOI: 10.1016/0020-711x(91)90063-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. We report on the kinetic properties of murine liver 4,5-dioxovaleric acid:L-alanine aminotransferase (DOVA transaminase). 2. The transamination of 4,5-dioxovaleric acid (DOVA) led to the production of delta-aminolevulinic acid. 3. L-Alanine was the preferred amino group donor among the common 20 amino acids. 4. The optimum pH of the reaction was 7-8. 5. A Km of 220 microM for DOVA and a Km of 970 microM for L-alanine were obtained. 6. The reaction was inhibited by each of the following: glyoxylate, beta-chloroalanine, methylglyoxal, delta-aminolevulinate, pyruvate, heme, and gabaculine. 7. None of several xenobiotic inducers of microsomal mixed function oxidases tested had a significant effect on DOVA transaminase activity in studies performed with murine primary hepatocyte cultures.
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Affiliation(s)
- C E McKinney
- Department of Zoology, University of Maryland, College Park 20742
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Beale SI, Weinstein JD. Chapter 5 Biochemistry and regulation of photosynthetic pigment formation in plants and algae. BIOSYNTHESIS OF TETRAPYRROLES 1991. [DOI: 10.1016/s0167-7306(08)60112-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Oh-hama T, Stolowich NJ, Scott AI. Characterization of the process of 5-aminolevulinic acid formation from glutamate via the C5 pathway in Clostridium thermoaceticum. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1991; 23:1417-20. [PMID: 1761150 DOI: 10.1016/0020-711x(91)90284-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. In vitro formation of 5-aminolevulinic acid (ALA) from glutamate required two enzyme fractions, separable on Blue Sepharose affinity chromatography, and a tRNA fraction, which can be replaced by Escherichia coli tRNA(Glu) in the reconstituted assay. 2. Gabaculine was shown to inhibit ALA formation in the complete assay as well as in a defined system consisting of only glutamate-1-semialdehyde and the enzyme fraction not retained on Blue Sepharose. 3. The results indicate that the enzyme system supporting ALA formation in Clostridium thermoaceticum is very similar to the tRNA(Glu)-dependent C5 pathway in plant plastids.
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Affiliation(s)
- T Oh-hama
- Department of Chemistry, Texas A & M University, College Station 77843-3255
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21
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Affiliation(s)
- G P O'Neill
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511
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22
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O'Neill GP, Söll D. Expression of the Synechocystis sp. strain PCC 6803 tRNA(Glu) gene provides tRNA for protein and chlorophyll biosynthesis. J Bacteriol 1990; 172:6363-71. [PMID: 2121711 PMCID: PMC526821 DOI: 10.1128/jb.172.11.6363-6371.1990] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In the cyanobacterium Synechocystis sp. strain PCC 6803 (Synechocystis 6803) delta-aminolevulinic acid (ALA), the sole precursor for the synthesis of the porphyrin rings of heme and chlorophyll, is formed from glutamate activated by acylation to tRNA(Glu) (G. P. O'Neill, D. M. Peterson, A. Schön, M. W. Chen, and D. Söll, J. Bacteriol. 170:3810-3816, 1988; S. Rieble and S. I. Beale, J. Biol. Chem. 263:8864-8871, 1988). We report here that Synechocystis 6803 possesses a single tRNA(Glu) gene which was transcribed as monomeric precursor tRNA and matured into the two tRNA(Glu) species. They differed in the extent of modification of the first anticodon base, 5-methylaminomethyl-2-thiouridine (O'Neill et al., 1988). The two tRNA species had equivalent capacities to stimulate the tRNA-dependent formation of ALA in Synechocystis 6803 and to provide glutamate for protein biosynthesis in an Escherichia coli-derived translation system. These results are in support of a dual role of tRNA(Glu). The levels of tRNA(Glu) were examined by Northern (RNA) blot analysis of cellular RNA and by aminoacylation assays in cultures of Synechocystis 6803 in which the amount of chlorophyll synthesized was modulated over a 10-fold range by various illumination regimens or by the addition of inhibitors of chlorophyll and ALA biosynthesis. In these cultures, the level of tRNA(Glu) was always a constant fraction of the total tRNA population, suggesting that tRNA(Glu) and chlorophyll levels are regulated independently. In addition, the tRNA(Glu) was always fully aminoacylated in vivo.
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Affiliation(s)
- G P O'Neill
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511
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23
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The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans. ORIGINS LIFE EVOL B 1990. [DOI: 10.1007/bf01808111] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Brown SB, Houghton JD, Vernon DI. Biosynthesis of phycobilins. Formation of the chromophore of phytochrome, phycocyanin and phycoerythrin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1990; 5:3-23. [PMID: 2111391 DOI: 10.1016/1011-1344(90)85002-e] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phycobiliproteins play important roles in photomorphogenesis and photosynthesis. The light-absorbing chromophores of the phycobiliproteins are linear tetrapyrroles (bilins) very similar in structure to the mammalian bile pigments. 5-Aminolaevulinate (5-ALA) is the first committed intermediate in phycobilin synthesis. The biosynthesis of 5-ALA, destined for phycobilins, occurs via the five-carbon pathway, now well established for tetrapyrrole synthesis in plants and distinct from the mammalian pathway. The phycobilins are formed by reduction of biliverdin which results from the synthesis and degradation of haem. This haem is an essential intermediate in the biosynthesis of phycobilins. Phycocyanobilin, the blue-green pigment found in certain algae and cyanobacteria, is formed from biliverdin via phytochromobilin, the chromophore of phytochrome. This leads to the likelihood that phytochromobilin is formed as an end product, or intermediate, in the synthesis of all phycobilins.
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Affiliation(s)
- S B Brown
- Department of Biochemistry, University of Leeds, U.K
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25
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Cloning and expression of a structural gene from Chlorobium vibrioforme that complements the hemA mutation in Escherichia coli. J Bacteriol 1990; 172:1656-9. [PMID: 2407729 PMCID: PMC208645 DOI: 10.1128/jb.172.3.1656-1659.1990] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Escherichia coli SASX41B carries the hemA mutation and requires delta-aminolevulinic acid for growth. Strain SASX41B was transformed to prototrophy with pYA1, a plasmid vector carrying a 5.8-kilobase insert of genomic DNA from the green sulfur bacterium Chlorobium vibrioforme. Cell extracts prepared from transformed cells are able to catalyze transfer of label from [1-14C]glutamate or [3,4-3H]glutamyl-tRNA to delta-aminolevullinic acid at rates much higher than extracts of wild-type cells can, whereas extracts prepared from untransformed strain SASX41B cells lack both activities. By comparing the relative abilities of glutamyl-tRNAs derived from several heterologous cell types to function as substrates for the dehydrogenase reaction in extracts of HB101 and SASX41B cells transformed by pYA1, it was determined that the expressed dehydrogenase in the transformed cells resembled that of C. vibrioforme and not that of E. coli. Thus it can be concluded that plasmid pYA1 contains inserted DNA that codes for a structural component of C. vibrioforme glutamyl-tRNA dehydrogenase which confers glutamyl-tRNA substrate specificity.
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26
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O'Neill GP, Chen MW, Söll D. δ-Aminolevulinic acid biosynthesis inEscherichia coliandBacillus subtilisinvolves formation of glutamyl-tRNA. FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03482.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Rieble S, Ormerod JG, Beale SI. Transformation of glutamate to delta-aminolevulinic acid by soluble extracts of Chlorobium vibrioforme. J Bacteriol 1989; 171:3782-7. [PMID: 2472378 PMCID: PMC210125 DOI: 10.1128/jb.171.7.3782-3787.1989] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Formation of the tetrapyrrole pigment precursor delta-aminolevulinic acid (ALA) from glutamate was detected and partially characterized in extracts of the strictly anaerobic green photosynthetic bacterial species Chlorobium vibrioforme by using assay methods derived from those developed for algae and cyanobacteria. ALA formation in Chlorobium extracts was saturated at 10 mM glutamate and required NADPH and ATP at optimal concentrations of 0.3 and 3 mM, respectively. Preincubation of the enzyme extract with RNase A destroyed the ALA-forming activity completely. Activity in the RNase-treated extract was restored by supplementation with Chlorobium RNA after addition of RNasin to block further RNase action. RNA from the cyanobacterium Synechocystis sp. strain PCC 6803 and Escherichia coli tRNAGlu also restored activity. Activity was inhibited 50% by 0.2 microM hemin. ALA formation was completely abolished by the addition of 5 microM 3-amino-2,3-dihydrobenzoic acid (gabaculine). These results indicate that Chlorobium extracts share with those of plants, eucaryotic algae, cyanobacteria, prochlorophytes, and methanogens the capacity for RNA-dependent ALA formation from glutamate.
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Affiliation(s)
- S Rieble
- Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912
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28
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Avissar YJ, Beale SI. Identification of the enzymatic basis for delta-aminolevulinic acid auxotrophy in a hemA mutant of Escherichia coli. J Bacteriol 1989; 171:2919-24. [PMID: 2656630 PMCID: PMC209995 DOI: 10.1128/jb.171.6.2919-2924.1989] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The hemA mutation of Escherichia coli K-12 confers a requirement for delta-aminolevulinic acid (ALA). Cell extract prepared from the hemA strain SASX41B was incapable of producing ALA from either glutamate or glutamyl-tRNA, whereas extract of the hem+ strain HB101 formed colorimetrically detectable amounts of ALA and transferred label from 1-[14C]glutamate and 3,4-[3H]glutamyl-tRNA to ALA. Extracts of both strains converted glutamate-1-semialdehyde to ALA and were capable of aminoacylating tRNAGlu. Glutamyl-tRNA formed by extracts of both strains could be converted to ALA by the extract of hem+ cells. The extract of hemA cells did not convert glutamyl-tRNA formed by either strain to ALA. However, the hemA cell extract, when supplemented in vitro with glutamyl-tRNA dehydrogenase isolated from Chlorella vulgaris cells, formed about as much ALA as did the unsupplemented hem+ cell extract. We conclude from these observations that the enzyme activity that is lacking in the ALA auxotrophic strain carrying the hemA mutation is that of glutamyl-tRNA dehydrogenase.
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Affiliation(s)
- Y J Avissar
- Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912
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Avissar YJ, Ormerod JG, Beale SI. Distribution of delta-aminolevulinic acid biosynthetic pathways among phototrophic bacterial groups. Arch Microbiol 1989; 151:513-9. [PMID: 2789025 DOI: 10.1007/bf00454867] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two biosynthetic pathways are known for the universal tetrapyrrole precursor, delta-aminolevulinic acid (ALA). In the ALA synthase pathway which was first described in animal and some bacterial cells, the pyridoxal phosphate-dependent enzyme ALA synthase catalyzes condensation of glycine and succinyl-CoA to form ALA with the loss of C-1 of glycine as CO2. In the five-carbon pathway which was first described in plant and algal cells, the carbon skeleton of glutamate is converted intact to ALA in a proposed reaction sequence that requires three enzymes, tRNA(Glu), ATP, Mg2+, NADPH, and pyridoxal phosphate. We have examined the distribution of the two ALA biosynthetic pathways among various genera, using cell-free extracts obtained from representative organisms. Evidence for the operation of the five-carbon pathway was obtained by the measurement of RNase-sensitive label incorporation from glutamate into ALA, using 3,4-[3H]glutamate or 1-[14C]glutamate as substrate. ALA synthase activity was indicated by RNase-insensitive incorporation of label from 2-[14C]glycine into ALA. The distribution of the two pathways among the bacteria tested was in general agreement with their previously established phylogenetic relationships and clearly indicates that the five-carbon pathway is the more ancient process, whereas the pathway utilizing ALA synthase probably evolved much later. The five-carbon pathway is apparently the more widely utilized one among bacteria, while the ALA synthase pathway seems to be limited to the alpha subgroup of purple bacteria.
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Affiliation(s)
- Y J Avissar
- Division of Biology and Medicine, Brown University, Providence, RI 02912
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Abstract
A hemA mutant of Escherichia coli containing a multicopy plasmid which complemented the mutation excreted 5-aminolevulinic acid (ALA) into the medium. [1-14C]glutamate was substantially incorporated into ALA by this strain, whereas [2-14C]glycine was not. Periodate degradation of labeled ALA showed that C-5 of ALA was derived from C-1 of glutamate. The synthesis of ALA by two sonicate fractions which had been processed by gel filtration and dialysis, respectively, was dependent on glutamate, ATP, NADPH, tRNA(Glu), and pyridoxal phosphate. tRNA(Glu) stimulated ALA synthesis in a concentration-dependent manner. Pretreatment with RNase reduced this stimulation. The amino acid sequence of the cloned insert, derived from the nucleotide sequence (J.-M. Li, C. S. Russell, and S. D. Cosloy, J. Cell Biol. 107:617a, 1988), showed no homology with any ALA synthase sequenced to date. These results suggest that E. coli synthesizes ALA by the C5 pathway from the intact five-carbon chain of glutamate.
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Affiliation(s)
- J M Li
- Department of Biochemistry, City College, City University of New York, New York 10031
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